Sheet pile connecting elements for use in pipe pile retaining walls

ABSTRACT

A weld-on connecting element fox a pipe sheet pile wall assembly includes ( 1 ) a base end configured to be welded to a pipe pile wall member, ( 2 ) an elongate neck strip having a substantially uniform width and having a length, extending from the base end along a predetermined main assembly direction (X) to an opposite end, which length is at least five times greater than said width, and ( 3 ) a claw strip provided at the opposite end having two claw strip members that form an oval-shaped lock chamber with their free ends facing each other to form an open jaw. The claw strip is adapted to partially surround and interlock with a head strip of another, matching connecting element. The space between the two claw-strip members is at least partially filled with a malleable sealant material, installed prior to welding the connector to the pipe piles.

BACKGROUND OF THE INVENTION

Sheet pile and pipe pile retaining walls have many uses. For example,they are often installed as barriers at seaport facilities to providevertical walls between land and sea.

FIG. 1 illustrates just such a retaining wall made of a row of steelpipes, arranged side by side, which were rammed into the sea floorbeneath the water. The pipes extend down through the sandy earth to thebedrock, providing a long lasting barrier, the life of which is limitedonly by the deleterious effects of corrosion.

FIG. 1 shows a pipe pile 32, one of many in the seaside retaining wall60. The wall supports the earth 62, on one side, from eroding andfalling into to the sea 64, on the other. The pipes of the wall,represented by the single pipe 32, pass through the sandy earth 66beneath the sea floor and are preferably of sufficient length to reachthe bedrock 68 below.

Although the average level of the sea varies with the tides within acertain range, indicated by the double arrow 70, and waves splashagainst the wall within a certain average range, indicated by the doublearrow 72, the wall of pipes is constructed considerably higher so as toprotect against storms and other contingencies. To achieve the totallength of pipe required, the pipes are transported to the constructionsite in convenient (e.g. 20 foot) lengths and welded end-to-end whenthey are installed. Depending on the total length of the pipe pilesrequired, and upon the preferences of the contractor, the pipe sectionscan either be rammed, section by section, and welded together during theramming process, or they can be welded first, end to end, and rammed asa single lengthy unit.

The pipes 32 may be connected together in the manner shown in FIGS. 2and 3, by sheet pile connecting elements 34 that are welded ontoopposite sides of each pipe pile prior to ramming the pipe, with itsconnector, into the earth. The connector on one side of the pipe isinterlocked with the mating connector on the previously installed,adjacent pipe prior to ramming, so that the connector of the rammed pipeslides along the mating connector of the installed pipe during theramming process.

FIG. 2 shows such a series of pipe piles 32, arranged along a horizontalline 33 and connected together by the intermediate connecting elements34, which are affixed to the external, curved surfaces of the piles bywelding.

FIG. 3 illustrates how two such pipe piles 32 are joined by suchconnecting elements 34, the details of which are presented in FIG. 4.Prior to ramming, a “male” connecting element 36 is welded to one sideof each pipe 32 and a “female” connecting element 38 is welded to theopposite side, over the entire length (or nearly the entire length) ofthe pipe. The pipes are then driven into the earth, one at a time, withthe male connecting element 36, welded to one pipe, inserted in andinterlocked with the female connecting element 38 that is welded to thenext, adjacent pipe.

Water leakage in the interlock joint between the male and femaleinterlocks can be substantially reduced by the use of a sheet pilinginterlock sealant, such as the commercial sealant available fromPilePro, LLC, Austin, Tex., under the registered trademark WADIT. Thissealant can be used with all types of hot rolled and cold formed sheetpiling interlocks in every type of environment (tropical to arctic), andparticularly in marine applications. In addition to seaside retainingwalls of the type shown in FIG. 1, such a sealant is useful in any sheetpiling project where water leakage through the wall presents a problem,such as with cofferdams and with cutoff walls for site remediation.

Tests have shown that leakage through sheet pile walls can be reduced by95% when interlock sealants are used. Sealed joint sheet pile cutoffwalls are anywhere from 100 to 10,000 times more effective asgroundwater flow barriers (sealed walls typically exhibit hydraulicconductivity in the 10-7 to 10-10 cm/sec range) than unsealed interlockwalls.

Although the sealant is normally inserted in the female interlock clawof Z-shaped or U-shaped sheet piling at the manufacturing facility, orsubsequently at the location of a distributor, prior to delivery of thesheet piling and its final installation at the job site, the sealant canalso be shipped to the job site where it is heated to its softeningtemperature in the range of 200 to 300° Fahrenheit and injected into theclaws of the sheet piles and/or sheet pile connectors just prior toramming. This latter procedure has been used for projects, such asseawalls of the type shown in FIG. 1, where it is necessary to weld thesheet pile connectors to sheet piling or pipe piling at the job site. Inthis case, the sealant is inserted in the claws of the connectingelements following the welding step to avoid heating the sealant duringwelding. The heat applied to the base of a connecting element by arcwelding is conducted through the element to its claw, causing thesealant to run and disperse. As a result, the claw does not sealproperly with the round head of the mating male connecting element.

Installing a sealant, such as WADIT®, in a connector claw at a job siteis extremely inconvenient at best, and adds an extra, time-consumingstep to the installation process.

SUMMARY OF THE INVENTION

It is a principal object of the present invention to provide a weld-onsheet pile connecting element which can be welded to a pipe pile duringinstallation at a project job site without causing a pre-installedsealant to run or disperse due to the heat of welding.

It is a further object of the present invention to provide a method ofinstalling a sealed and welded pipe pile retaining wall using weld-onsheet pile connectors for which the sealant has been applied to theclaws of the connectors prior to welding.

These objects, as well as other objects which will become apparent fromthe discussion that follows, are achieved, in accordance with thepresent invention, by providing a weld-on connecting element, of thetype having a female interlock claw strip, with such a size and shapethat sufficient heat is dispersed during the welding process to avoidsoftening and/or melting of a sealant having a melting temperature inthe range of 200 to 300° F.

The sealant WADIT®, in particular, has a melting temperature ofapproximately 260° F., which is within this range.

More particularly, the present invention provides for a weld-on profileconnector forming part of an elongate sheet pile connecting element foruse in a pipe pile wall assembly comprising (a) a plurality ofsupporting, elongate pipe pile wall members with their longitudinal axesarranged substantially in parallel and disposed along a commonhorizontal line, and (b) a plurality of sheet pile connecting elementsarranged in parallel with, and welded to, the pipe pile wall members.

The weld-on connector is formed of two separate connector elements: botha male and a female element. The female element has (1) a base endconfigured to be welded to a pipe pile wall member; (2) an elongate neckstrip having a substantially uniform width and having a length,extending from the base end along a predetermined main assemblydirection (X) to an opposite end, which is at least five times greaterthan the width; and (3) a claw strip provided at the opposite end havingtwo claw strip members that form an oval-shaped lock chamber with theirfree ends facing each other to form an open jaw. The claw strip isadapted to partially surround and interlock with a head strip of theother, matching weld-on connecting element 36.

According to the invention, the space between the two claw-strip membersis at least partially filled with a malleable sealant material,installed prior to welding the connector to the pipe piles.

In a preferred embodiment of the weld-on connector element, the two clawstrip members are mirror images of each other about the main assemblydirection (X). Also, in this embodiment the width of the neck strip issubstantially equal to the width of each of the claw strip members.

To insure that the sealant does not overheat during welding, it ispreferable that the length of the neck strip be not only five, but atleast six times greater than its width. This relationship is achieved,for a neck strip having a width of approximately 11.5 mm, if the lengthof the element, extending from a bottom surface of the base end,configured to be welded to a pipe pile wall member, to a point at thecenter of the lock chamber, is equal to approximately 88 mm, so that thelength of the neck strip alone is approximately 76 mm.

For a full understanding of the present invention, reference should nowbe made to the following detailed description of the preferredembodiments of the invention as illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a seaside retaining wall (not toscale) of the type to which the present invention relates.

FIG. 2 is an illustration of a row of pipe piles of the type to whichthe present invention relates.

FIG. 3 is a plan view showing two pipe piles linked together by male andfemale connecting elements, welded to the exterior pipe pile surfaces.

FIG. 4 is a detailed plan view of the male and female connectingelements shown in FIG. 3.

FIG. 5 is a detailed plan view showing another embodiment of male andfemale connecting elements that may be used to connect pipe piles.

FIG. 6 is a plan view of two pipe piles linked by two Z-shaped sheetpiles.

FIG. 7 is a detailed plan view of the male connecting element shown inFIGS. 3 and 4.

FIG. 8 is a detailed plan view of the female connecting element shown inFIGS. 3 and 4.

FIG. 9 is a plan view of the female connecting element of FIGS. 3, 4 and8 with the sealant inserted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention will now be describedwith reference to FIGS. 1-9 of the drawings. Identical elements in thevarious figures are designated with the same reference numerals.

According to the invention, it has been discovered that when the sealantis pre-inserted in the claw of the long, weldable connecting element ofthe type shown in FIGS. 4 and 8, prior to welding, heat applied duringthe welding process does not have a deleterious effect on the sealant.This is apparently due to the fact that the heat of welding is notconducted sufficiently rapidly down the length of the connecting elementto melt or otherwise impair the sealant.

FIG. 5 shows another type of sheet pile connector 40 that may be usedbetween adjacent pipes 32 to connect the pipes closely together, thusincreasing the strength of the retaining wall. This connector 40, whichis similar to the connector described in detail in the U.S. Pat. No.7,168,214, comprises a short male element 42 having a head strip 44 anda short female element having an corresponding, interlocking claw strip46.

Conventional Z-shaped sheet piles may also be used as connectors betweenthe load bearing pipe piles, allowing the pipes to be spaced muchfarther apart in cases where great wall strength is not required. FIG. 6shows two pipe piles 32, also arranged side by side and longitudinallyin parallel, which are separated by two Z-shaped sheet piles 50 and 52connected to male and female connecting elements 46 and 42,respectively. These connecting elements are, in turn, welded to theexternal surfaces of the pile piles.

If the sealant is pre-applied to the short, weldable female connectingelement 46 prior to ramming, the sealant, which hardens somewhat butremains fluid with a high viscosity, melts in part and flows out of theclaw when the connecting element is welded. Thereafter, when therespective male connecting element is rammed into the female connector,the resulting seal is adequate.

FIGS. 7 and 8 detail the preferred dimensions of the male and femaleconnectors 36 and 38 respectively, that are illustrated in FIG. 4 ininterlocked relationship.

FIG. 7 shows the end face of the male connecting profile strip(connecting element) 36. This profile strip 36 has a constant crosssection when viewed longitudinally, and is in the form of a welded-onstrip. For this, the connecting profile strip 36 possesses a base 62,shown to the left in FIG. 7, having a slightly arched cross-sectionalshape that simplifies welding of this base onto the arched cross-sectionof the pipe pile 32.

A neck strip 64 projects from the base 62 along a main assemblydirection X whose free end is shaped into a head strip 66. The headstrip 66 possesses an oval cross section with the main axis of the ovalhead strip 66 extending perpendicular to the main assembly direction X.The head strip 66 matches the shape and form of the head strip of aconventional ball-and-socket sheet pile connection.

The greatest dimension a of the head strip 66 along the main assemblydirection X is about 2 to 2.5 times the thickness b of the neck strip64. The length c of the neck strip 64 viewed along the main assemblydirection X is approximately five times of the greatest dimension d ofthe head strip 66 viewed along the main assembly direction X, as isshown by the dashed imaginary projection of the oval.

FIG. 8 shows the end face of a the female connection profile strip(connecting element) 38 based. The connection profile strip 38 alsopossesses a base 72 with arched shape, from which a neck strip 74projects along the main assembly direction X. A claw strip 76 with aC-shaped cross section is formed at the free end of the neck strip 74.

The C-shaped claw strip 76 is formed of two arc-shaped, mirror-imageclaw strips 78 that form a lock chamber 80 and whose free ends pointtoward each other defining a jaw 82. The arc-shaped progression of theclaw strips 78 provide the lock chamber 80 with an essentially ovalcross section. The lock chamber 80 is thus of such dimensions that itcan receive the head strip 66 of the male connecting profile strip 60shown in FIG. 7.

In the illustrated embodiment, the greatest dimension e of the lockchamber 80 perpendicular to the main assembly direction X is larger thanthe greatest dimension a of the head strip 66 of the male connectingprofile strip 60 perpendicular to the main assembly direction X by afactor of about 1.2.

The jaw 82 of the claw strip 76 is, in turn, shaped such that the centerlines 84 of the free ends of the two claw strips 78 intersect with theaxis of symmetry of the claw strip 76 at a point S outside the jaw 82.For this, the separation of the intersection point S to the jaw 82 ispreferably 0.5 to 1.5 times the width f of the claw strips 78 which, inturn, is approximately the same as the width of the neck strip 74. Thelength g of the neck strip 74 essentially corresponds to the length c ofthe neck strip 64 of the male connecting profile strip 36. The lockchamber 80 of the claw strip 76, thus dimensioned, ensures a secure holdof the claw strip 76, while the head strip 66 on the other hand may bepivoted within a predetermined pivot range within the lock chamber 80.

FIG. 9 is an end view of the weldable female connecting element 36 withthe sealant 86 pre-installed in the claw in accordance with theinvention. It has been discovered that when the sealant is pre-insertedin the claw of a long connecting element of this type prior to welding,heat applied during the welding process does not have a deleteriouseffect on the sealant. This is apparently due to the fact that the heatof welding is not conducted sufficiently rapidly down the length of theconnecting element to melt or otherwise impair the sealant.

By providing the female connecting element with a neck strip having alength that is at least five times its width, and preferably even morethan six times its width, the heat of welding that is conducted from thebase end of the element to the claw strip at its opposite end isinsufficient to melt the sealant.

There has thus been shown and described an improved sheet pileconnecting elements for use in pipe pile retaining walls, which fulfillall the objects and advantages sought therefor. Many changes,modifications, variations and other uses and applications of the subjectinvention will, however, become apparent to those skilled in the artafter considering this specification and the accompanying drawings whichdisclose the preferred embodiments thereof. All such changes,modifications, variations and other uses and applications which do notdepart from the spirit and scope of the invention are deemed to becovered by the invention, which is to be limited only by the claimswhich follow.

1. A weld-on sheet pile connecting element for use in a pipe pile wallassembly comprising (a) a plurality of supporting, elongate pipe pilewall members with their longitudinal axes arranged substantially inparallel and disposed along a common horizontal line, and (b) aplurality of sheet pile connecting elements arranged in parallel with,and welded to, said pipe pile wall members, said weld-on connectingelement comprising a base end configured to be welded to a pipe pilewall member, an elongate neck strip having a substantially uniform widthand having a length, extending from the base end along a predeterminedmain assembly direction to an opposite end, which length is at leastfive times greater than said width, and a claw strip provided at theopposite end having two claw strip members that form an oval-shaped lockchamber with their free ends facing each other to form an open jaw, saidclaw strip being adapted to partially surround and interlock with a headstrip of another, matching connecting element; wherein the space betweenthe two claw-strip members is at least partially filled with a malleablesealant material.
 2. The weld-on profile connector of claim 1, whereinthe two claw strip members are mirror images of each other about themain assembly direction.
 3. The weld-on profile connector of claim 1,wherein the length of the neck strip is at least six times greater thanits width.
 4. The weld-on profile connector of claim 1, wherein thewidth of the neck strip is substantially equal to the width of each ofthe claw strip members.
 5. The weld-on profile connector of claim 1,wherein the melting point of the sealant material is in the range of 200to 300° F.
 6. The weld-on profile connector of claim 1, wherein themelting point of the sealant material is substantially equal to 260° F.7. The weld-on profile connector of claim 1, having a length, from abottom surface of the base end configured to be welded to a pipe pilewall member to a point at the center of said lock chamber, equal toapproximately 88 mm.
 8. The weld-on profile connector of claim 1,wherein the length of the neck strip is approximately 76 mm.
 9. Theweld-on profile connector of claim 1, wherein the width of the neckstrip is approximately 11.5 mm.
 10. In a method of installing a pipepile wall assembly comprising (a) a plurality of supporting, elongatepipe pile wall members with their longitudinal axes arrangedsubstantially in parallel and disposed along a common horizontal line,and (b) a plurality of sheet pile connecting elements arranged inparallel with, and welded to, said pipe pile wall members, said weld-onconnecting element comprising a base end configured to be welded to apipe pile wall member, an elongate neck strip having a substantiallyuniform width and having a length, extending from the base end along apredetermined main assembly direction to an opposite end, which lengthis at least five times greater than said width, and a claw stripprovided at the opposite end having two claw strip members that form anoval-shaped lock chamber with their free ends facing each other to forman open jaw, said claw strip being adapted to partially surround andinterlock with a head strip of another, matching connecting element;said method comprising: at least partially filling the space between thetwo claw-strip members with a malleable sealant material; and thereafterwelding the said connecting element to a pipe pile; and thereafterramming said pipe pile into the ground.
 11. The method defined in claim10, wherein the two claw strip members are mirror images of each otherabout the main assembly direction.
 12. The method defined in claim 10,wherein the length of the neck strip is at least six times greater thanits width.
 13. The method defined in claim 10, wherein the width of theneck strip is substantially equal to the width of each of the claw stripmembers.
 14. The method defined in claim 10, wherein the melting pointof the sealant material is in the range of 200 to 300° F.
 15. The methoddefined in claim 10, wherein the melting point of the sealant materialis substantially equal to 260° F.
 16. The method defined in claim 10,wherein said connecting element has a length, from a bottom surface ofthe base end configured to be welded to a pipe pile wall member to apoint at the center of said lock chamber, equal to approximately 88 mm.17. The method defined in claim 10, wherein the length of the neck stripis approximately 76 mm.
 18. The method defined in claim 10, wherein thewidth of the neck strip is approximately 11.5 mm.